Annular after reactor with sound attenuator for use in a jet engine test cell and test stand

Abstract

An annular after reactor is aligned axially with the direction of exhaust flow from the exhaust port of a jet engine under static test. Located near the front end of the reactor is a first set of gas injectors. A second set of gas injectors are located downstream from the first set of gas injectors within the reactor. The first set of gas injectors inject natural gas into the jet engine exhaust, while the second set of gas injectors inject ammonia into the jet engine exhaust. The natural gas when ignited raises the temperature of the jet engine exhaust which incinerates the particulate matter in the exhaust. Ammonia injected into the exhaust stream functions as a reductant to eliminate up to 90% of the NO X compounds in the exhaust stream. The reactor includes a jet engine exhaust buster assembly for substantially reducing noise generated by a jet's engine's exhaust.

What is claimed is:  
     
       1. An apparatus for removing particulate matter and nitrogen oxides from an exhaust stream generated by a jet engine under test, said apparatus comprising: 
       an annular after reactor aligned axially with a direction of exhaust flow from an exhaust port of said jet engine, said annular after reactor having a cylindrical shaped outer casing, and an interior;  
       first injecting means located within the interior of said annular after reactor for injecting natural gas into said exhaust stream to remove said particulate matter from said exhaust stream when a temperature for said exhaust stream is raised to a first temperature range;  
       igniting means positioned adjacent said first injecting means to ignite said natural gas injected into said exhaust stream raising the temperature of said exhaust stream to said first temperature range which removes said particulate matter from said exhaust stream; and  
       second injecting means located within the interior of said annular after reactor downstream from said first injecting means, said second injecting means injecting ammonia into said exhaust stream to remove said nitrogen oxides from said exhaust stream when the temperature of said exhaust stream is within a second temperature range; and  
       sound attenuating means positioned within said annular after reactor for substantially reducing noise levels within said annular after reactor.  
     
     
       2. The apparatus of  claim 1  wherein said first and second injecting means each comprise a set of spoke shaped injectors positioned perpendicular to said cylindrical shaped outer casing, each set of said spoke shaped injectors extending inward into the interior of said annular after reactor. 
     
     
       3. The apparatus of  claim 1  wherein said first temperature range comprises a temperature range of 1850° F. to 2200° F. 
     
     
       4. The apparatus of  claim 1  wherein said second temperature range comprises a temperature range of 1650° F. to 1850° F. 
     
     
       5. The apparatus of  claim 1  further comprising a layer of ceramic material positioned inside of said cylindrical shaped outer casing, said layer of ceramic material being affixed to said cylindrical shaped outer casing. 
     
     
       6. The apparatus of  claim 1  wherein said first and second injecting means each comprise: 
       a tubular gas injection ring vertically positioned within the interior of said annular after reactor;  
       first and second fuel feed lines connected to said tubular gas injection ring, said first and second fuel feed lines providing support for said tubular gas injection ring;  
       said tubular gas injection ring having a first plurality of equally spaced gas injection nozzles located around an outer circumference thereof and a second plurality of equally spaced gas injection nozzles located around an inner circumference thereof;  
       a centrally located gas injection device positioned within the interior of said annular after reactor, said gas injection device being aligned with said tubular gas injection ring;  
       said gas injection device having six equally spaced gas injection nozzles positioned around the circumference thereof; and  
       a third fuel feed line connected to said gas injector device, said third fuel feed line being used to position said gas injection device centrally within the interior of said annular after reactor and to provide support for said gas injection device.  
     
     
       7. The apparatus of  claim 1  wherein said sound attenuating means comprises a honeycomb structure positioned within the interior of said annular after reactor, said honeycomb structure having a plurality of openings through which said exhaust stream passes, each of said plurality of openings having an interior surface which approximates a circle having a diameter of between one inch and three inches. 
     
     
       8. The apparatus of  claim 1  wherein said sound attenuating means comprises: 
       a plurality of concentric rings vertically positioned within the interior of said annular after reactor; and  
       a support structure having a centrally located support hub and a plurality of equally spaced apart support rods affixed to each of said concentric rings, one end of each of said support rods being attached to said support hub and the opposite end of each of said support rods being attached to an interior surface of said annular after reactor.  
     
     
       9. The apparatus of  claim 1  further comprising a layer of an acoustic insulating material affixed to an interior surface of said annular after reactor. 
     
     
       10. The apparatus of  claim 1  wherein said sound attenuating means reduces said noise levels by approximately fifteen decibels. 
     
     
       11. An apparatus for removing particulate matter and nitrogen oxides from an exhaust stream generated by a jet engine under test, said apparatus comprising: 
       an annular after reactor aligned axially with a direction of exhaust flow from an exhaust port of said jet engine, said annular after reactor having a cylindrical shaped outer casing, and an interior;  
       a layer of ceramic material positioned inside of said cylindrical shaped outer casing, said layer of ceramic material being affixed to said cylindrical shaped outer casing;  
       a first gas injector located within the interior of said annular after reactor for injecting natural gas into said exhaust stream to remove said particulate matter from said exhaust stream when a temperature for said exhaust stream is raised to a first temperature range of 1850° F. to 2200° F.;  
       a gas ignition device positioned adjacent said first gas injector to ignite said natural gas injected into said exhaust stream raising the temperature of said exhaust stream to said first temperature range to remove said particulate matter from said exhaust stream; and  
       a second gas injector located within the interior of said annular after reactor downstream from said first gas injector, said second gas injector injecting ammonia into said exhaust stream to remove said nitrogen oxides from said exhaust stream when the temperature of said exhaust stream is within a second temperature range of 1650° F. to 1850° F.;  
       a diffuser positioned at the front end of said annular after reactor, said diffuser being aligned axially with the direction of exhaust flow from an exhaust port of said jet engine; and  
       a jet engine exhaust buster assembly positioned in a forward portion of said annular after reactor, said jet engine exhaust buster assembly being aligned axially with the direction of exhaust flow from an exhaust port of said jet engine;  
       said diffuser and said jet engine exhaust buster operating in combination to substantially reduce noise levels within said annular after reactor.  
     
     
       12. The apparatus of  claim 11  wherein said first and second gas injectors each comprise a set of spoke shaped injectors positioned perpendicular to said cylindrical shaped outer casing, each set of said spoke shaped injectors extending inward into the interior of said annular after reactor. 
     
     
       13. The apparatus of  claim 11  wherein said first and second gas injectors each comprise: 
       a tubular gas injection ring vertically positioned within the interior of said annular after reactor;  
       first and second fuel feed lines connected to said tubular gas injection ring, said first and second fuel feed lines providing support for said tubular gas injection ring;  
       said tubular gas injection ring having a first plurality of equally spaced gas injection nozzles located around an outer circumference thereof and a second plurality of equally spaced gas injection nozzles located around an inner circumference thereof;  
       a centrally located gas injection device positioned within the interior of said annular after reactor, said gas injection device being aligned with said tubular gas injection ring;  
       said gas injection device having six equally spaced gas injection nozzles positioned around the circumference thereof; and  
       a third fuel feed line connected to said gas injector device, said third fuel feed line being used to position said gas injection device centrally within the interior of said annular after reactor and to provide support for said gas injection device.  
     
     
       14. The apparatus of  claim 11  wherein said gas ignition device comprises a heated wire. 
     
     
       15. The apparatus of  claim 11  wherein said jet engine exhaust buster assembly comprises a honeycomb structure having a plurality of openings through which said exhaust stream passes, each of said plurality of openings having an interior surface which approximates a circle having a diameter of between one inch and three inches. 
     
     
       16. The apparatus of  claim 11  wherein said jet engine exhaust buster assembly comprises: 
       a plurality of concentric rings vertically positioned within the interior of said annular after reactor; and  
       a support structure having a centrally located support hub and a plurality of equally spaced apart support rods affixed to each of said concentric rings, one end of each of said support rods being attached to said support hub and the opposite end of each of said support rods being attached to an interior surface of said annular after reactor.  
     
     
       17. The apparatus of  claim 11  further comprising a layer of an acoustic insulating material affixed to an interior surface of said annular after reactor. 
     
     
       18. The apparatus of  claim 11  wherein said diffuser and said jet engine exhaust buster operating in combination reduce said noise levels by approximately fifteen decibels. 
     
     
       19. An apparatus for removing particulate matter from an exhaust stream generated by a jet engine under test, said apparatus comprising: 
       an annular after reactor aligned axially with a direction of exhaust flow from an exhaust port of said jet engine, said annular after reactor having a cylindrical shaped outer casing, and an interior;  
       a layer of ceramic material positioned inside of said cylindrical shaped outer casing, said layer of ceramic material being affixed to said cylindrical shaped outer casing;  
       a gas injector located within the interior of said annular after reactor for injecting natural gas into said exhaust stream to remove said particulate matter from said exhaust stream when a temperature for said exhaust stream is raised to a temperature range of 1850° F. to 2200° F.;  
       a gas ignition device positioned adjacent said first gas injector to ignite said natural gas injected into said exhaust stream raising the temperature of said exhaust stream to said first temperature range to remove said particulate matter from said exhaust stream;  
       a diffuser positioned at the front end of said annular after reactor, said diffuser being aligned axially with the direction of exhaust flow from an exhaust port of said jet engine; and  
       a jet engine exhaust buster assembly positioned in a forward portion of said annular after reactor, said jet engine exhaust buster assembly being aligned axially with the direction of exhaust flow from an exhaust port of said jet engine;  
       said jet engine exhaust buster assembly comprising a honeycomb structure having a plurality of openings through which said exhaust stream passes, each of said plurality of openings having an interior surface which approximates a circle having a diameter of between one inch and three inches;  
       said diffuser and said jet engine exhaust buster operating in combination to substantially reduce noise levels within said annular after reactor.  
     
     
       20. The apparatus of  claim 19  wherein said gas injector comprises a set of spoke shaped injectors positioned perpendicular to said cylindrical shaped outer casing, said set of spoke shaped injectors extending inward into the interior of said annular after reactor. 
     
     
       21. The apparatus of  claim 19  wherein said gas injector comprises: 
       a tubular gas injection ring vertically positioned within the interior of said annular after reactor;  
       first and second fuel feed lines connected to said tubular gas injection ring, said first and second fuel feed lines providing support for said tubular gas injection ring;  
       said tubular gas injection ring having a first plurality of equally spaced gas injection nozzles located around an outer circumference thereof and a second plurality of equally spaced gas injection nozzles located around an inner circumference thereof;  
       a centrally located gas injection device positioned within the interior of said annular after reactor, said gas injection device being aligned with said tubular gas injection ring;  
       said gas injection device having six equally spaced gas injection nozzles positioned around the circumference thereof; and  
       a third fuel feed line connected to said gas injector device, said third fuel feed line being used to position said gas injection device centrally within the interior of said annular after reactor and to provide support for said gas injection device.  
     
     
       22. The apparatus of  claim 19  wherein said gas ignition device comprises a heated wire. 
     
     
       23. The apparatus of  claim 19  wherein said diffuser and said jet engine exhaust buster operating in combination reduce said noise levels by approximately fifteen decibels.